There have conventionally been provided nitride semiconductor light emitting devices in each of which a nitride semiconductor laminate body is formed on a C-plane sapphire substrate, and light is extracted not only from the nitride semiconductor laminate body but also from a lateral surface of the sapphire substrate.
In order to improve light extraction efficiency from a lateral surface of the sapphire substrate, the above-described nitride semiconductor light emitting device needs to have the sapphire substrate with a certain thickness and a roughened lateral surface.
The C-plane sapphire substrate, however, has no cleavage plane perpendicular to the C-plane, and is made of a material with high hardness and chemical stability. These properties make it difficult to divide the thick sapphire substrate into chips and to roughen the lateral surface of the sapphire substrate.
When a sapphire substrate is divided by point-scribing first and then breaking, the division begins at a point only approximately 10 μm deep from the surface of sapphire substrate. Accordingly, the thickness of the sapphire substrate needs to be within approximately 100 μm.
When a sapphire substrate is divided into chips by firstly performing an ablation process with a laser beam focused on a surface of the sapphire substrate and then by breaking, the division begins at a position only approximately 30 μm deep from the surface of a sapphire substrate. For this reason, the thickness of the sapphire substrate needs to be within approximately 130 μm.
After the sapphire substrate is divided into chips by breaking, each chip thus formed has lateral surfaces in a cracked state. For this reason, there is a problem that it is difficult to roughen such lateral surfaces.